Make it clearer that not every Postgres character set can be used as a server-side character set.
Make it clearer that not every Postgres character set can be used as a
server-side character set.

kmjungersen/PostgresXL,50wu/gpdb,cjcjameson/gpdb,postmind-net/postgres-xl,rvs/gpdb,Postgres-XL/Postgres-XL,chrishajas/gpdb,edespino/gpdb,ovr/postgres-xl,CraigHarris/gpdb,chrishajas/gpdb,royc1/gpdb,50wu/gpdb,rvs/gpdb,CraigHarris/gpdb,oberstet/postgres-xl,yazun/postgres-xl,xuegang/gpdb,lintzc/gpdb,yuanzhao/gpdb,xinzweb/gpdb,janebeckman/gpdb,tangp3/gpdb,atris/gpdb,lisakowen/gpdb,lintzc/gpdb,cjcjameson/gpdb,xuegang/gpdb,foyzur/gpdb,ashwinstar/gpdb,0x0FFF/gpdb,Quikling/gpdb,atris/gpdb,snaga/postgres-xl,lpetrov-pivotal/gpdb,kaknikhil/gpdb,lisakowen/gpdb,Quikling/gpdb,xinzweb/gpdb,pavanvd/postgres-xl,lpetrov-pivotal/gpdb,Postgres-XL/Postgres-XL,ashwinstar/gpdb,foyzur/gpdb,janebeckman/gpdb,yuanzhao/gpdb,Chibin/gpdb,greenplum-db/gpdb,edespino/gpdb,lintzc/gpdb,cjcjameson/gpdb,techdragon/Postgres-XL,edespino/gpdb,randomtask1155/gpdb,zeroae/postgres-xl,jmcatamney/gpdb,tpostgres-projects/tPostgres,foyzur/gpdb,jmcatamney/gpdb,CraigHarris/gpdb,royc1/gpdb,lintzc/gpdb,atris/gpdb,yuanzhao/gpdb,snaga/postgres-xl,CraigHarris/gpdb,50wu/gpdb,tangp3/gpdb,50wu/gpdb,rubikloud/gpdb,atris/gpdb,chrishajas/gpdb,kaknikhil/gpdb,CraigHarris/gpdb,arcivanov/postgres-xl,lpetrov-pivotal/gpdb,oberstet/postgres-xl,pavanvd/postgres-xl,edespino/gpdb,randomtask1155/gpdb,0x0FFF/gpdb,ahachete/gpdb,kaknikhil/gpdb,yazun/postgres-xl,oberstet/postgres-xl,ahachete/gpdb,zaksoup/gpdb,arcivanov/postgres-xl,CraigHarris/gpdb,chrishajas/gpdb,kaknikhil/gpdb,50wu/gpdb,Quikling/gpdb,foyzur/gpdb,royc1/gpdb,kaknikhil/gpdb,foyzur/gpdb,xuegang/gpdb,ahachete/gpdb,zaksoup/gpdb,Postgres-XL/Postgres-XL,royc1/gpdb,zeroae/postgres-xl,jmcatamney/gpdb,tpostgres-projects/tPostgres,lintzc/gpdb,greenplum-db/gpdb,kmjungersen/PostgresXL,Chibin/gpdb,ovr/postgres-xl,0x0FFF/gpdb,randomtask1155/gpdb,snaga/postgres-xl,50wu/gpdb,tangp3/gpdb,oberstet/postgres-xl,edespino/gpdb,lpetrov-pivotal/gpdb,rubikloud/gpdb,lintzc/gpdb,ashwinstar/gpdb,pavanvd/postgres-xl,kaknikhil/gpdb,Quikling/gpdb,Postgres-XL/Postgres-XL,zaksoup/gpdb,janebeckman/gpdb,xinzweb/gpdb,xuegang/gpdb,royc1/gpdb,janebeckman/gpdb,xuegang/gpdb,xuegang/gpdb,zaksoup/gpdb,xuegang/gpdb,adam8157/gpdb,snaga/postgres-xl,rubikloud/gpdb,lisakowen/gpdb,chrishajas/gpdb,Chibin/gpdb,chrishajas/gpdb,lisakowen/gpdb,adam8157/gpdb,lpetrov-pivotal/gpdb,techdragon/Postgres-XL,ahachete/gpdb,xinzweb/gpdb,chrishajas/gpdb,kaknikhil/gpdb,zeroae/postgres-xl,ahachete/gpdb,yuanzhao/gpdb,50wu/gpdb,tangp3/gpdb,lisakowen/gpdb,50wu/gpdb,zaksoup/gpdb,Chibin/gpdb,adam8157/gpdb,randomtask1155/gpdb,edespino/gpdb,tangp3/gpdb,zaksoup/gpdb,Quikling/gpdb,0x0FFF/gpdb,rubikloud/gpdb,rubikloud/gpdb,atris/gpdb,ashwinstar/gpdb,arcivanov/postgres-xl,adam8157/gpdb,ahachete/gpdb,rvs/gpdb,randomtask1155/gpdb,Chibin/gpdb,tpostgres-projects/tPostgres,rvs/gpdb,atris/gpdb,yuanzhao/gpdb,adam8157/gpdb,pavanvd/postgres-xl,ashwinstar/gpdb,Quikling/gpdb,janebeckman/gpdb,kmjungersen/PostgresXL,rvs/gpdb,xinzweb/gpdb,ovr/postgres-xl,atris/gpdb,Quikling/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,royc1/gpdb,royc1/gpdb,postmind-net/postgres-xl,jmcatamney/gpdb,postmind-net/postgres-xl,Quikling/gpdb,0x0FFF/gpdb,Quikling/gpdb,tangp3/gpdb,jmcatamney/gpdb,Quikling/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,lisakowen/gpdb,greenplum-db/gpdb,adam8157/gpdb,yuanzhao/gpdb,foyzur/gpdb,lintzc/gpdb,0x0FFF/gpdb,rubikloud/gpdb,janebeckman/gpdb,ovr/postgres-xl,janebeckman/gpdb,Postgres-XL/Postgres-XL,Chibin/gpdb,kaknikhil/gpdb,yazun/postgres-xl,zaksoup/gpdb,kmjungersen/PostgresXL,postmind-net/postgres-xl,postmind-net/postgres-xl,techdragon/Postgres-XL,lisakowen/gpdb,yuanzhao/gpdb,rubikloud/gpdb,zeroae/postgres-xl,cjcjameson/gpdb,tpostgres-projects/tPostgres,cjcjameson/gpdb,rvs/gpdb,cjcjameson/gpdb,rvs/gpdb,Chibin/gpdb,lpetrov-pivotal/gpdb,janebeckman/gpdb,edespino/gpdb,lpetrov-pivotal/gpdb,ahachete/gpdb,janebeckman/gpdb,rvs/gpdb,Chibin/gpdb,lintzc/gpdb,yuanzhao/gpdb,adam8157/gpdb,xuegang/gpdb,zaksoup/gpdb,yuanzhao/gpdb,kaknikhil/gpdb,edespino/gpdb,ovr/postgres-xl,xinzweb/gpdb,cjcjameson/gpdb,yazun/postgres-xl,0x0FFF/gpdb,yuanzhao/gpdb,lintzc/gpdb,CraigHarris/gpdb,pavanvd/postgres-xl,tangp3/gpdb,kaknikhil/gpdb,randomtask1155/gpdb,cjcjameson/gpdb,lisakowen/gpdb,xinzweb/gpdb,atris/gpdb,kmjungersen/PostgresXL,CraigHarris/gpdb,xinzweb/gpdb,janebeckman/gpdb,arcivanov/postgres-xl,Chibin/gpdb,xuegang/gpdb,ashwinstar/gpdb,rvs/gpdb,techdragon/Postgres-XL,zeroae/postgres-xl,tangp3/gpdb,tpostgres-projects/tPostgres,royc1/gpdb,lpetrov-pivotal/gpdb,oberstet/postgres-xl,jmcatamney/gpdb,rubikloud/gpdb,adam8157/gpdb,CraigHarris/gpdb,cjcjameson/gpdb,randomtask1155/gpdb,greenplum-db/gpdb,foyzur/gpdb,snaga/postgres-xl,cjcjameson/gpdb,0x0FFF/gpdb,greenplum-db/gpdb,Chibin/gpdb,arcivanov/postgres-xl,edespino/gpdb,ahachete/gpdb,greenplum-db/gpdb,arcivanov/postgres-xl,randomtask1155/gpdb,yazun/postgres-xl,chrishajas/gpdb,techdragon/Postgres-XL,edespino/gpdb,rvs/gpdb,foyzur/gpdb,greenplum-db/gpdb